The present invention relates to miniature electrical connectors for connecting very small multi-conductor cables to closely spaced terminal pads on printed circuits or the like.
In many situations where electrical signals are being carried among separate subassemblies of complex electrical and electronic devices reduced size contributes greatly to the usefulness or convenience of the devices or of certain portions of them. To that end, cables including extremely small conductors are now available, and it is practical to manufacture very closely spaced terminal pads accurately located on circuit boards or the like. It is therefore desirable to have a connector of reduced size, to interconnect such cables and circuit boards repeatedly, easily, and reliably, and with a minimum adverse effect on electrical signal transmission in a circuit including such a connector. As electrical signals with higher frequencies are employed it becomes more important to maintain shielding and provide a waveguide or transmission line configuration as near as possible to the connection of a cable to a circuit board or the like.
For some electronic circuit equipment it is necessary to be able to replace and reconnect cables carrying large numbers of independent high frequency signals on extremely small conductors. It is important to be able to effect reliable interconnection of each cable conductor to a respective circuit terminal with a minimum effect on overall circuit impedance, and within a minimum amount of space.
In many applications where cables are connected and disconnected from circuit boards it is desired to have a wiping contact, so that insertion of a connector reliably establishes good electrical contact between the connector and the circuit board terminal pad surfaces.
It is well known to mold supportive bodies of dielectric plastic around contact arrays for multi-conductor connectors. It is still desired, however, to produce connectors with contact spacings smaller than can be made in that way.
Robin et al. U.S. Pat. No. 4,571,014 discloses a modular connector for use in high frequency circuits, in which planar shields are stacked between circuit boards each having a row of female connector sockets, to produce a multi-conductor connector having several aligned rows of sockets arranged in a grid. The construction disclosed, however, results in a connector of a considerably larger size than is desired for interconnecting very small multi-conductor cables with circuits.
Okamoto et al. U.S. Pat. No. 5,145,413 discloses a connector in which several lead terminals are held side-by-side and are molded within an insulating resin to form a linear array, with a plurality of such arrays being contained in a connector housing.
Yatsu et al. U.S. Patent No. 5,195,899 discloses matable plug and jack connectors. In the plug connector disclosed, several conductors are held in small holes defining each of a pair of arrays of such conductors each having a male signal terminal in the form of an exposed contact point, and a planar male ground connector is located between the two arrays of male signal terminals.
Dudek et al. U.S. Pat. No. 5,122,065 discloses a connector in which walls having conductive surface layers surround signal conductors to form grounded tunnel-like passages through which the signal conductors extend, and wiping contact surfaces are provided at a front edge of the connector.
Pierini et al. U.S. Pat. No. 3,689,865 discloses a multi-conductor electrical connector for connection to terminal pads on both sides of a circuit board through wiping contacts in the form of flat springs, but the contacts are attached separately to a supporting spacer, which requires that the contacts be spaced apart from one another a distance greater than is desired for connecting very small multi-conductor cables.
What is still needed, then, is a multi-conductor connector, and a method of making such a connector, which is capable of providing reliable wiping contact with spring pressure, with closer spacing than has previously been possible, and which can be used in high frequency applications with minimal adverse effects on signal transmission.